Life is one negotiation after another, though too few of us are equipped for battle. Formidable deal-makers like Warren Buffett, Bill Clinton and sports agent Scott Boras tend to be born, not made.

Yet, talk to negotiating pros from the worlds of government, finance and media and they'll admit there is at least some science to this art. Winning every point is rarely an option, of course, but if you keep a few principles in mind, you can tilt things in your favor — whether you're signing a peace treaty or just angling for a raise.

know your negotiating boundaries

If you remember one thing about negotiating, it should be this: It's not the maneuvering once you're in the trenches, but rather the preparation before sitting down at the table that counts.

That means taking the time to define what you want, what you are willing to accept and at what point you will walk away. It also means doing enough research to know what the other side wants — and how far they are willing to go to get it.

“The most important information deals with the other side — what drives them, how they measure success and what are their strengths and weaknesses," says Mladen Kresic, founder of K&R Negotiation Associates, a Ridgefield, Connecticut-based consultancy, and author of Negotiate Wisely in Business and Technology.

Richard Shell, a professor at the Wharton School of Business and author of The Art of Woo, about persuasive selling tactics, takes that notion a step further. “Know your own strengths and weaknesses,” he says. "By that, I mean know the kinds of negotiations that you enjoy and are good at — and what ones are going to trip you up and make you anxious."

know your enemy and earn trust

That also means choosing the right people to do the negotiating in the first place. For example, one-off transactions favor competitive types who see the negotiation as a game they must win (think Donald Trump.) If you are naturally more at ease with building consensus and nurturing long-term relationships, let someone else take the lead.

Next step: Try to establish some trust, says George Mitchell, ex-senate majority leader and former chair of the International Commission on Disarmament in Northern Ireland. "In Ireland, I tried to set up a process that people felt was fair in that they had a chance to make their case," he says. "I made it a point to tell them I [come from a system] where we had unlimited debate. I sometimes regretted that [later] when I was listening to 15-, 16-, 18-hour speeches, but it was important for helping things move forward."

know your zopa

Before you start haggling, establish what negotiating textbooks lovingly call the ZOPA, or zone of possible agreement. "There's always a large area of overlapping interest,” says Andrew Heyward, president of CBS News from 1996 to 2005. “It's helpful to define that up front so you can refer back to it later, when the petty details threaten to bog you down.”

Heyward learned about not sweating the details during a heated negotiation with a star news anchor a few years ago. “The star's agent presented me with a long set of demands, ranging from the relevant to the ridiculous," he recalls. "The numbers involved were large enough that I had to go to my boss, Leslie Moonves, an excellent negotiator in his own right, for guidance.

"I had carefully thought out a detailed response to each of the many issues, down to the smallest perk. To my surprise, Leslie didn't even want to hear most of the counter-arguments; instead, as I went down the laundry list, he kept saying 'fine.’ Rather than engaging in hand-to-hand combat on every point, he chose to focus on the few that were truly important and contentious.”

know when to walk away

Finally, if you can't find the ZOPA, have enough discipline to walk away. That advice comes from a guy who has negotiated a few deals and doesn't like to lose: Sandy Weill, former chief executive of Citigroup.

"I would always get very excited and very disappointed" when a deal didn't pan out, admits Weill. "Sometimes [the price] just doesn't make sense to you, or the [target company] has a certain culture that you don't feel is going to fit together. You've got to have the discipline to walk away. Lo and behold, something better would come along in six months or a year, which in most cases was a much better deal."